A six-speed double clutch transmission is known from DE 43 30 170 C2, which is configured with a so-called double clutch on the side of the gearbox input, which consists of two friction-locked shift elements. A drive torque of a drive motor that is applied on a motor shaft according to a transmission capacity adjusted in the respective shift elements is conducted to a first main gearbox input shaft or to a second gearbox input shaft mounted on the main gearbox input shaft and configured as a hollow shaft. The two gearbox input shafts are connected torsion-resistant to a respective gear wheel and these gear wheels mesh, in turn, with gear wheels that are respectively connected torsion-resistant to a countershaft. The two countershafts are arranged concentrically with respect to each other, whereupon a countershaft configured as a hollow shaft is mounted on a further main countershaft.
In order to adjust the different gear ratios, the six-speed, double clutch transmission is configured with further gear wheel pairs that can be connected via synchronizations, wherein the respectively adjusted overall gear transmission is forwarded according to the converted drive torque of the power plant, via a gearbox output shaft, that is arranged coaxially with respect to the gearbox inlet.
It is disadvantageous here, however, that the high gearing forces that are actively connected with the gear wheel pairs in the area of the countershaft that is configured as a hollow shaft (and which will be called the hollow countershaft below), which are caused by the different gear ratios of the gear wheel pairs between the gearbox input shafts and the countershaft, must be transferred via the bearing between the hollow countershaft and the main countershaft or main countershaft gear if there is a differential speed and, in addition, the forces that are conducted toward the main hollow countershaft must be introduced into the housing via the bearing mechanisms of the main countershaft within the housing if there is a renewed speed difference. This arrangement is characterized by unfavorable load characteristic values that have, as a consequence, a short service life of the gearbox, which is undesirable from the point of view of the operating costs of a motor vehicle over its entire service life.
It is, therefore, an object of the invention to furnish a multi-speed transmission of countershaft design, which has advantageous load characteristic values as well as a long service life.